Devices for rinsing a body cavity are known in the art wherein change-over of a suction line to preset values is performed by signal contacts of an operating unit for a medical instrument such as a shaver and application of this signal for controlling a suction/rinse device. Simultaneously, a change-over of the suction line between shaver and drainage cannula takes place.
A disadvantage of such a device is that, when a shaver is used, the operating conditions “on” and “off” are transmitted to the system by the signal contacts, typically a foot switch. In the simplest case, this may take place by signal lines having plug connections. This is expensive, in particular in construction. Furthermore, there are functional sources of faults, for instance, due to bad contacts by contact corrosion and the like. Finally, the plug connections are subject, due to frequent operation, to wear. A particularly important drawback is that the shaver must be compatible with the device, since a signal exclusively comprises the digital information “on” and “off”, and consequently the control system in a control unit must be set for a second medical instrument to be employed, for instance, the shaver. If such a setting is not possible, a specific medical instrument only may be operated by the control unit. As a result, there is no compatibility between a single control unit and several different medical instruments and/or identical medical instruments of different manufacturers and different specifications with regard to the flow resistance.
Finally, it is believed disadvantageous in prior known devices that with the signaling of the operating condition from “off” to “on” of the second medical instrument on the feed side of the body cavity, an immediate increase of the flow takes place, while the increased discharge of fluid through the second medical instrument is comparatively slow. Thus a risk of a potentially medically dangerous pressure peak in the body cavity is present.